Medication errors in primary care practice are an important cause of morbidity but the extent of these errors is largely unknown and effective interventions for reducing these errors need to be developed and tested. The Practice Partner Research Network (PPRNet), a practice-based research network among primary health care providers practicing in 38 States who use a common electronic medical record (EMR), has developed a quality improvement model for successfully translating research into primary care practice termed PPRNet-TRIP. PPRNet- TRIP incorporates prioritization of evidence-based quality philosophies, involving all staff (teamwork), delivery system redesign, patient activation, and EMR tools for individualized and population-based medicine. PPRNet-TRIP is implemented in practice settings through a combination of practice performance reports, practice site visits, network meetings, and webbased tools. The purpose of the activities proposed in the application is to conduct a demonstration project among 20 PPRNet practices. The project is intended to develop a set of medication safety measures relevant for primary care, incorporate these measures in practice performance reports sent quarterly to participating practices, and assess the impact of PPRNet- TRIP on the incidence of these errors. The project will be 3 years in duration. During the first 9 months, a preliminary set of medication safety indicators developed by the research team will be refined, using a consensus development process among the participating practices. Programs will be developed to add these medication safety measures to the quarterly PPRNet practice reports. A two year intervention will then be conducted, including the performance reports, network meetings, and practice site visits, to help practices systematize their use of the medication safety clinical decision support features in their EMR system. These features include warnings for drug allergies, drug-drug interactions, drug-disease interactions, incorrect dosages, and drug ineffectiveness;and prompts for therapeutic monitoring to prevent adverse drug events. After two years the impact of the intervention on the incidence of medication errors will be assessed. A mixed-method process evaluation will also be conducted to assess project. The findings will then be disseminated to other PPRNet practices and more broadly through presentations and publications.